Marcell Cornelius Coetzee, born on 8 May 1991 in Potchefstroom, Transvaal, Republic of South Africa, is a South African rugby union player. He currently plays for the Blue Bulls in the United Rugby Championship and the Currie Cup. Coetzee's regular position is flanker.

Standing at an impressive height of 1.93 meters (6 feet 4 inches) and weighing 117 kilograms (258 pounds), Coetzee possesses a formidable physical presence on the field. He attended Port Natal High School, where his rugby journey began to take shape.

Coetzee's professional career kicked off when he made his Super Rugby debut for the Sharks on 7 May 2011, showcasing his skills and potential. His ability to offload the ball in tackles drew comparisons to the renowned Sonny Bill Williams, establishing him as an exciting talent in South African rugby.

Heyneke Meyer, the coach of the Springboks at the time, recognized Coetzee's talent and included him in the national squad for a test series against England. On 9 June 2012, Coetzee made his Springbok test debut in Durban, marking an important milestone in his career.

In 2015, Coetzee ventured abroad to join the Honda Heat, a team in the Japanese Top League, for the 2015-2016 season. He gained valuable experience playing in a different rugby environment before making a move to the Irish Pro12 side Ulster in the 2016-2017 season. Coetzee signed a three-year deal with Ulster and showcased his skills despite facing recurring knee injury problems.

Coetzee's impressive form in the 2020-21 season, where he emerged as the joint top try-scorer and earned the Pro14 Players' Player of the Season accolade, led to his return to South Africa. In December 2020, it was confirmed that Coetzee would join the Bulls, signing a three-year deal. His arrival added strength and experience to the Blue Bulls' squad.

Throughout his career, Coetzee has achieved various honors, including winning the Currie Cup in 2021 with the Blue Bulls and reaching the final of the Pro14 Rainbow Cup in the same year. His outstanding performances have earned him a place in the United Rugby Championship "Dream Team" for the 2020-21 and 2021-22 seasons.

Coetzee's work rate, defensive prowess, and ability to make an impact on attack have made him a valuable asset in the back row. Despite encountering injury setbacks, Coetzee's determination and performances have solidified his position as an influential player in both club and international rugby.